Alternative option for `match_arm_leading_pipes`?

I would really like an option for match_arm_leading_pipes which only forces matches to the same branch onto new lines with a pipe. For example:

match foo {
    aaa => ()
    bbb | ccc | ddd => ()
    eee => ()
} 

becomes

match foo {
    aaa => ()
    bbb
    | ccc 
    | ddd => ()
    eee => ()
} 

I personally like this change because it prevents overly-cramped long multi-match arms while also making it clear which "blocks" correspond to which arms. Is this possible already? If not, could someone point me in the right direction for adding a PR?

Start by tracing the existing match_arm_leading_pipes configuration and the formatter logic that handles multi-pattern match arms. Compare its current output with the requested example, then determine how an alternative option should be represented and tested. Done means the option produces the requested line breaks and preserves existing behavior when disabled.